From 8e2839ac39a1888b3bf7d12a5f4c28ebbbe0b4e8 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Sun, 25 May 2025 12:44:23 +0000
Subject: [PATCH 1/2] Initial plan for issue


From 013207a751e54412eedf5e30b4ee15a511efc45a Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Sun, 25 May 2025 12:51:34 +0000
Subject: [PATCH 2/2] Fix UTF-8 BOM handling in MonacoPreviewHandler

Co-authored-by: lei9444 <39758135+lei9444@users.noreply.github.com>
---
 .../MonacoPreviewHandler/MonacoPreviewHandlerControl.cs  | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/modules/previewpane/MonacoPreviewHandler/MonacoPreviewHandlerControl.cs b/src/modules/previewpane/MonacoPreviewHandler/MonacoPreviewHandlerControl.cs
index 68dde66e3c6c..a7c2c1a466ca 100644
--- a/src/modules/previewpane/MonacoPreviewHandler/MonacoPreviewHandlerControl.cs
+++ b/src/modules/previewpane/MonacoPreviewHandler/MonacoPreviewHandlerControl.cs
@@ -389,6 +389,15 @@ private void InitializeIndexFileAndSelectedFile(string filePath)
                 }
 
                 fileReader.Close();
+                
+                // Remove BOM character if present to avoid encoding issues when converting to base64
+                // BOM character might be present as U+FEFF even though StreamReader should normally handle it
+                if (fileContent.Length > 0 && fileContent[0] == '\uFEFF')
+                {
+                    fileContent = fileContent.Substring(1);
+                    Logger.LogInfo("Removed UTF-8 BOM character from file content");
+                }
+                
                 _base64FileCode = Convert.ToBase64String(System.Text.Encoding.UTF8.GetBytes(fileContent));
                 Logger.LogInfo("Reading requested file ended");
             }